Stereolab42

I have a 1988 560SL as my "fun" convertible. It performs well for its era but I've been toying with replacing it with an R230 55/65 since I've gotten too used to the performance of my daily driver AMGs (which have always been 63s). This particular 2005 SL65 seems like it's been maintained well -- the PO just did the motor mounts -- and nothing appears broken. However I wasn't really "blown away" by the performance like I expected, and honestly it seemed a big sluggish at typical speeds. If I jumped on the accelerator it went forward like a freight train, yes, but it didn't really "feel" like a super-responsive car. Am I judging this SL65 too harshly based on my experiences with modern tuned 63s? I note that the AMGs of this area don't have the equivalent of Comfort/Sport/Sport+ which makes a huge difference in throttle response in modern AMGs. Would a Eurocharged/Renntech tune help this? I've also heard conflicting reports about the SL55 perhaps feeling nimbler and more aggressive than the SL65 despite having less power overall, what about that? (I have vague plans to test-drive a local SL55 soon to test that theory.)

whoover

I had a 2006 S65 and it had a bit of turbo lag (compared with my '19 E63S) but never felt sluggish. That engine has 500 lb-ft of torque at 1,500 rpm and moved at any speed. I'd suspect something is wrong with the turbos. Intercooler problems were common.

Viper98912

The 65 definitely "winds up", and when it hits, you hold on. With an old 5 speed transmission and somewhat conservative programming and a smooth non-emotional purring V12, you learn to get on the gas just slightly earlier than you're used to so you can hold on for the ride when it hits.

Stereolab42

Hmm. Yeah, that's what it felt like, but I'm definitely used to the power coming on earlier after being traumatized by the S/S+ modes of my modern tuned AMGs. I note that both Eurocharged and Renntech have combo TCU/ECU tunes, and I wonder if that makes the car respond more aggressively. Can anyone here with those tunes comment on before/after?

Quadrobenz

I think something may not be functioning correctly in the SL65 you test drove. I had a 2005 SL600. It launched hard and quick, no problem spinning tires above about 1/3 throttle from launch. After it was Eurocharged tuned it was harder hitting off the line and all around faster than the 2007 E63 6.2L NA with a 7 speed we owned at the same time. At the same time we also had a 2006 S65 with a Eurocharged tune. It was in no way sluggish or non responsive. It was so hard hitting with small throttle movements I had to use C mode rather than S or M when I had passengers to stop the complaining.
We currently have a 2017 SL65, a 2015 S65 and a 2018 E63S. None of these cars are in any way non responsive or sluggish feeling. The least responsive (but not in any way slow) is the E63S because the bottom end torque is so much less than the 6L V12's.

Das Geld 2

Could be, but my 55 feels more responsive than my cousins N/A 63

mikekaro

I added a Pedal Box to mine to change throttle response. Completely different in how my 05 SL65 behaves. Tune is next...

eatmycrackers

Add the acceleration upgrade (I forget the name of the maker). My SL65 has one and you can toggle it between OFF, ON and SPORT mode or something like that. In the most aggressive mode you REALLY feel the difference. It is cheap, ~$300 mod which can be turned off at the press of a button.

I also have a Renntech tune but I would say the faster acceleration button is the best bang for your buck.

bobterry99

To be clear, Speedbooster, Pedal Box, and similar products only negligibly improve the maximum acceleration time of the car. They simply make the valve body more sensitive to incremental changes in throttle position, and this deceives some people into believing their maximum acceleration has improved.

Speedbooster has a demonstration video which shows a stock throttle taking c. 2 seconds to fully open from its closed position. The video shows that with their Speedbooster the throttle opens instantaneously. Yet anyone with a Chinese-cloned Star Diagnosis can see that with the stock pedal the throttle on an R230 opens instantaneously...

Quadrobenz

From Stereolab42's comments it still sounds to me like something is not right with the car.
The 65 engine is unique in that it is the only MB production engine that without protective tuning exceeds the warranty rating of the transmission-738 ft-lb. As a result the TCU/ECU programming pulls timing from the engine at hard throttle to manage the torque. This begins at about 2400rpm. As a result of this and other tuning features the car will feel heavy compared to other AMG's. A tune will make a dramatic difference in the part throttle feel and performance of a 65 engine. The tune fundamentally changes the spark advance map as well as some fine tuning of the fuel map. Thus my comments above about the change in the post tune driving experience in my S65. The tune on the SL600 made a big change in full throttle power but was undetectable at part throttle driving. Fuel mileage was unchanged in city driving but the S65 mileage increased by 2.5mpg at highway cruise. This was from the timing and fuel map changes. There was minimal change in the SL600 mileage. The tune provider stated at the time the S65 tune added about 100ft-lb torque and about 80hp compared to factory ratings.

Stereolab42

Still wish I had another local SL65 to compare with but the next closest is 350 miles away. I did test-drive a 2013 SLK55 listed at the same price and was very impressed. It's almost 1000 pounds lighter than the SL65 and felt more responsive and nimble. Did not pull quite as hard straight-line obviously but it was plenty fast. Absent a tune I'll take the SLK55 anyday. Now the question is with a tune, how much would the SL65 wake up? It's also worth noting the SLK55 can be tuned as well (though unfortunately not close to the added %age in hp/tq the SL65 can). It's just tough for me to take the risk on the SL65. On the off chance there's anyone in the Bay Area with a tuned SL65 R230 who wants to let me drive theirs, drop me a PM.

(I also tried many times to contact the company that makes the only full coilover/ABC conversion kit for the SL65 to inquire about availability but they choose not to respond. I have zero intention of wrestling with ABC hydraulic issues so that does make the decision easier for me...)

Quadrobenz

If you liked the SLK55 then you should buy it. The cost of ownership will be less than an SL65.

Das Geld 2

Coilver over on the 65 is like trying to turn a station wagon at 80 mph

Stereolab42

I just did, bought it today. Would have liked to own a V12 at least once in my life but a pristine 2013 SLK55 with only 22k miles was too hard to turn down. Would still have given the SL65 a harder look if I could have compared more than one example, but it wasn't to be. (Also test-drove a 2018 Mustang GT convertible for the lulz and it was straight garbage... good god who buys those things? American muscle was a hundred times better 50 years ago except for 0-60.)

iridium18

Stereolab42 - CONGRATS on the purchase ! ENJOY !

smithwn55

Ditch the sl 65 idea and get a sl55 amg and forget about lag. Also save yourself thousands/year on maintenance.

Instant power, no bs and no drama. Make certain to purchase an 07 or 08 however due to ABS and other less important chasis/mechanical upgrades.

My stock 08 dyno'd at 445hp and 503 lb ft tq. You can easily increase both by 70+ for a few thousand dollars if stock performance isn't enough. Just my $.02

BlownV8

No lag on my biturbo V12. As can be seen with recent 1/4 mile runs, the 55 can be a beast. The 65 with a tune is bumping 700 hp and around 600 RWHP on pump gas. As far as maintenance, the only difference is the coilpacks and once those are upgraded they are trouble free.

The 55 is a great car but I like the power of the V12 and the sound is amazing. I have yet to hear a MB that sounds as good as my V12. Then again, it's not stock and sounds more like a Pagani than a standard MB.

bobterry99

I believe you meant to type "ABC" instead of "ABS", and the notion that this was upgraded is unfounded. An '07 and '08 have a small performance boost but likely nothing else over other years.

850csi

My understanding is that just about anything requiring work in the engine bay is substantially more expensive due to space constraints? Aren’t motor mounts a $4k+ engine out job on the V12s?

smithwn55

I did mean ABC, thanks. Also, my understanding is the 07 and 08 got the 2nd generation ABC system.
Thanks

BlownV8

If you are spending $4k on a motor mount job, you have issues. Can drop the subframe a bit and change them. Engine does not need to come out.

bobterry99

Yes, and if you compare the two generations you will see that the second is basically the same as the first with much of the cost of manufacture engineered out.

Das Geld 2

Saying ABC 2 same as ABC 1?

I thought some improvements behind the scenes...guess not..good to know

smithwn55

Bottom lines are;
1) 07 and 08 models have lower risk of major mechanical failure associated with ABC system installed in the sl55's
2) The sl65 for reasons above and others not enumerated have higher overall costs of ownership due to maintenance issues associated with their beautiful, but problematic, V12 engines.

I could have bought either car. And I'm not slamming anyone that purchased the 65. It just wasn't worth the risk and hassle to me.

BlownV8

The V12 engine is very dependable. ABC, on the other hand, is not. V12's prior to 2003 had the oil cooler leaks but the bi-turbo's have no real weak points that I'm aware. Now, there are electric issues with the early coilpacks but have yet to have any issues with the updated versions. I've only taken two of the bi-turbo engines to over 100k miles each so my experience may be limited.